Welcome to Plbg.com
Thank you to all the plumbing professionals who offer their advice and expertise

Over 700,000 strictly plumbing related posts

Welcome to Plbg.com (also known as PlumbingForum.com) where plumbing advice, education, information, help and suggestions are provided by some of the most experienced plumbers and plumbing contractors anywhere who all wish to "give back" to society. Since 1996 we have been free without popup or other invasive ads and known to be the best online STRICTLY PLUMBING advice site. If you have questions about plumbing, toilets, sinks, faucets, drains, sewers, water filters, venting, water heating, showers, pumps, and other strictly PLUMBING related issues then you've come to the right place. Please refrain from asking or discussing legal questions, or pricing, or where to find and/or purchase products, or any business issues, or for contractor referrals, or any other questions or issues not specifically related to plumbing. Keep all posts positive and absolutely no advertising. Our site is completely free, without ads or pop-ups and we don't track you. We absolutely do not sell your personal information. We are made possible by:  

Post New
Search
Log In
How to Show Images
Newest Subjects
 5/8" copper pipe?
Author: Anonymous User

My house was built in the late 50's. The main supply line in the basement is 5/8" in diameter. I'd like to do some plumbing work, but not redo everything all it once. I'm having a hard time trying to find reducers that go down to 5/8" pipe. They don't seem to exist. I've measured and remeasured to verify this dimension. No one carries this size fitting. Do they actually exist?

Any suggestions?

Post Reply

 Re: 5/8
Author: Edward429451 (CO)

Try asking for 1/2" fittings. 5/8" OD is 1/2" pipe. If its out of spec, it could have frozen and be expanded as existing. If so it could probably be swaged up.



Post Edited

Post Reply

 Re: 5/8" copper pipe?
Author: jimmy-o (CA)

Let me get technical, not to be smart, but to let you know where you are.

The water lines in a house are actually not copper PIPE, they are copper TUBE. The rigid (straight) peices are known as hard copper tube, and anything which can be bent in your hands is called soft copper tube.

Copper tube comes in type K, L, and M. They have different wall thickness, but the outside diameters are the same, so fittings work for any type.

K,L,M copper is referred to by its NOMINAL size, which is given as the APPROXIMATE INSIDE diameter. The OUTSIDE diameter for any K,L,M tube is EXACTLY 1/8" bigger than the nominal size.

SO, what everyone refers to as 1/2" copper pipe is actually type K,L, or M harde copper tube and the outside diameter is EXACTLY 5/8". 3/4" copper is 7/8" OD and 3/8" copper is 1/2" OD.


Wait, we're not done. There is another type of copper tube known as type ACR, or simply referred to as refrigeration tube. This type is referred to by actual OD. So 1/2 ACR is 1/2 OD. 5/8 ACR is 5/8" OD.


Now, is 5/8ACR the same as 1/2 K,L,M. Well, lets be brief and say that you wouldn't put type K,L,M in a refrigeration system; but for all practical purposes ACR would worok in water if you have the proper sized fittings.

Your 5/8" OD tube should accept standard 1/2" copper (NOT refrigeration) fittings. If it does not, something strange may have happened as mentioned by another post such as swaging or expansion from freezing.

Sorry to be so windy, but with this information you now know more than some people around town who call themselves plumbers.

Post Reply

 Re: 5/8" copper pipe?
Author: PlumberManDan (IA)

Could have not said it better JIMMY.

Plumbermandan

Post Reply

 Re: 5/8" copper pipe?
Author: cynwes (VT)

Dear Jimmy-o,

Your explanation of a 5/8 OD pipe (tube) is sooooo helpful. Thank you, thank you, for being technical and "windy". I really appreciate all the details, and now I understand why my very dear plumber friend kept telling me that in all his 20+ years as a professional plumber, he's never seen a 5/8" toilet supply line. It's simply because he calls it 1/2", and he has not yet come to my house to do the work, so I was trying to give him info about the pipe via the telephone, and I had carefully measured the OD with calipers. We had a comical yelling match as I insisted it was 5/8 and he insisted his giant plumbing supply company had no such size. But now I get it, thanks to you. It would be like someone not realizing that 2x4 lumber actually measures 1 1/2 x 3 1/2. Nothing like a clear explanation from one who knows.....

Thanks again,
Cyn

Post Reply





Please note:
  • Inappropriate messages or blatant advertising will be deleted. We cannot be held responsible for bad or inadequate advice.
  • Plbg.com has no control over external content that may be linked to from messages posted here. Please follow external links with caution.
  • Plbg.com is strictly for the exchange of plumbing related advice and NOT to ask about pricing/costs, nor where to find a product (try Google), nor how to operate or promote a business, nor for ethics (law) and the like questions.
  • Plbg.com is also not a place to ask radiant heating (try HeatingHelp.com), electrical or even general construction type questions. We are exclusively for plumbing questions.

Search for plumbing parts on our sponsor's site:




Special thanks to our sponsor:
PlumbingSupply.com


Copyright© 2025 Plbg.com. All Rights Reserved.